The development of hepatocellular carcinoma (HCC) is a serious and feared malignancy, which is increasing in prevalence in the United States. HCC is associated with chronic liver damage secondary to viral infection by Hepatitis B or C Viruses (HBV and HCV) and/or alcohol. Clearly it would be desirable to discover the genes and genetic pathways that lead to HCC progression. Biomarkers that could be used to detect HCC and to predict tumor progression (invasion/metastasis) are desperately needed in the clinical management of patients at high risk for HCC. Furthermore, little is known about germline alterations that could predispose some patients to HCC. All of these goals address the mission of the National Cancer Institute's plan to create a comprehensive human cancer genome atlas. While some insight has been gained in the somatic changes that can occur in HCC, it is likely that much remains to be learned. An unbiased screen for somatic mutations that could cause HCC or accelerate malignancy after initiation by liver damage could provide a list of candidate genes to examine for alterations in human HCC. The identification of HCC cancer genes, and the patterns in which these mutations occur in individual cases, will certainly guide future therapies. It is the main goal of this grant to model HCC using a novel system for random, Sleeping Beauty (SB) transposon-based, somatic insertional mutagenesis developed by Drs. Largaespada and Dupuy. Methods to induce HCC by transposition of SB transposon vectors in hepatocytes and their precursors will be used to find genes consistently mutated by transposon insertion with and without background liver cirrhosis. Candidate HCC genes will be tested for their ability to cause cancer by SB mediated gene transfer into recipient mice. Cancer HCC genes will also be analyzed in human HCC samples for alterations in silico using public and published databases. Relevance: This project seeks to define what genes, when altered in liver cells, cause hepatocellular carcinoma (HCC). It is critical to know what genes cause HCC so that effective therapies for this cancer can be developed. A mouse model of HCC will be created in which all the mutated genes that cause the HCC can be identified.